<!DOCTYPE html>
<html>
<head>
    <style>
        #foo {
            height: 50px;
            box-sizing: border-box;
        }
        #bar {
            border-bottom-width: 0px;
            box-sizing: border-box;
        }
    </style>
</head>
<body>
    <hr id="foo">
    <hr id="bar">
</body>
</html>

